Just went through this same with the 89. There are two 'mega' wiring connectors on the riders side of the block. Sure enough, there was hidden heat/wire damage, as they had popped off the holder strip and laid up against the block. The 'signal return' wire was completely burned through. When repaired, and the connectors remounted to the strip, it did quite well.
Then the fuel pump failed, no fuel pressure at rail. The engine was 'sucking' just enough to idle, but bogged at any throttle. I can not say if there was any connection between the two faults.